Iterative method for estimating productivity index (PI) values in maximum reservoir contact (MRC) multilateral completions

Abstract

A process for determining the productivity index of a multilateral completion using data from individual laterals and data from commingled well tests is disclosed. The process includes 1) determining the productivity index for each single lateral by iteratively altering the productivity index until the individual lateral flowrate based on a known reservoir pressure is matched and 2) further determining the productivity index by iteratively altering the productivity index until the commingled flowrate is matched. The productivity index may be used to set wellhead pressures and inline control valve (ICV) settings for production.

Description

BACKGROUNDField of the Disclosure[0001]Embodiments of the disclosure generally relate to multilateral wells and, more specifically, determining the production capabilities of multilateral completions.Description of the Related Art[0002]In the recovery of hydrocarbons from subterranean formations having hydrocarbon-bearing reservoirs, wellbores are drilled with multiple highly deviated or horizontal portions that extend through separate hydrocarbon-bearing production zones. Such “multilateral wells” include branches or laterals from a motherbore that extend into the separate hydrocarbon-bearing production zones. Multilateral well have increased in importance during the past decade and may be used for hydrocarbon production from “tight” reservoirs.[0003]As result of the increasing use of multilateral wells, multilateral well modeling and performance prediction techniques have become increasingly important for a variety of purposes. Such techniques are used by production engineers to d...

AI Technical Summary

Benefits of technology

The patent text describes a method and system for determining the productivity of a multilateral well that has multiple laterals. The method involves determining initial productivity indices for each lateral and well test, and then using these indices to calculate intermediate and final productivity indices. These productivity indices can then be used to evaluate the performance of the well and make adjustments to the wellhead pressure and control valves. The system includes a computer-readable memory and a productivity index processor to automate the calculations and make the process more efficient. The technical effects of the patent text include improved accuracy in evaluating the performance of multilateral wells and faster and more cost-effective well testing.

Problems solved by technology

Existing numeric models are inefficient and time-consuming when used for production engineering purposes.

Existing analytic models simply calculate the sum of productivity of the individual branches or laterals of a multilateral well; however, this approach is rarely accurate and does not accurately capture the interplay between branches or laterals.

The existing approaches fail to properly evaluate the competition effects of inflow performance and interface effects of commingled production.

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